This invention was made in the course of, or under, a contract with the Energy Research and Development Administration.
One of the problems that can occur when two pieces of material are welded together is the formation of small voids or pores in the weld joint. These voids can be detected through the use of radiographic techniques; however, to accurately determine their size, metallographic sectioning and measurement with a microscope is required, thus destroying the sample. As can be seen in FIG. 2 of the drawings, the size of the image of a void on X-ray sensitive film C is dependent on the proportional distances of the void between the film and the X-ray source. Sphere A and sphere B are identical in size; however, sphere A appears to be larger than sphere B on the radiographic images of the plate.
Thus, a need exists to provide a means of measuring voids in welds which (1) does not require destroying the weld, and (2) is sufficiently accurate to use as a standard in quality control operations. The present invention was conceived to meet this need in a manner to be described hereinbelow.